Check if object is deep frozen
Checks if an object is deeply frozen.
- Use recursion.
- Use
Object.isFrozen()on the given object. - Use
Object.keys(),Array.prototype.every()to check that all keys are either deeply frozen objects or non-object values.
const isDeepFrozen = obj => Object.isFrozen(obj) && Object.keys(obj).every( prop => typeof obj[prop] !== 'object' || isDeepFrozen(obj[prop]) ); const x = Object.freeze({ a: 1 }); const y = Object.freeze({ b: { c: 2 } }); isDeepFrozen(x); // true isDeepFrozen(y); // false
